[LTP] [PATCH v3 1/2] lib: Extend -D flag to support multiple debug levels

[Li Wang via ltp <ltp@lists.linux.it>]

This patch extends the LTP debugging framework by introducing multiple
levels of verbosity for the '-D' command line option. Instead of a simple
on/off toggle, it now allows developers to specify whether they want debug
output exclusively from the test process, or from both the test and library
processes.

The supported debug levels are:
  -D1 (-D): Enable debug logs for the test process only
  -D2     : Enable verbose debug logs for both the test and library processes

Suppress all debug logs if no '-D' flag passed (by default behavoir).

Signed-off-by: Li Wang <liwang@redhat.com>
---

Notes:
    v2 --> v3:
    	* do not print "Enabling debug info" for -D0
    	* drop the -D0 support becase it's the default behavor.

 doc/developers/debugging.rst |  7 +++++++
 lib/tst_test.c               | 27 ++++++++++++++++-----------
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/doc/developers/debugging.rst b/doc/developers/debugging.rst
index 181e5b096..dcb287bb6 100644
--- a/doc/developers/debugging.rst
+++ b/doc/developers/debugging.rst
@@ -12,6 +12,13 @@ The LTP framework supports ``TDEBUG`` flag test debug messages. These
 messages can be enabled using the ``-D`` parameter or setting ``LTP_ENABLE_DEBUG=1``
 environment variable (see :doc:`../users/setup_tests`).
 
+The ``-D`` parameter also supports the following verbosity levels:
+
+  ``-D1`` (or ``-D``): Enable debug logs for the test process only.
+  ``-D2``: Enable verbose debug logs for both the test and library processes.
+
+Suppress all debug logs if no '-D' flag passed (by default behavoir).
+
 Tracing and debugging syscalls
 ------------------------------
 
diff --git a/lib/tst_test.c b/lib/tst_test.c
index 239494b6f..e01c14638 100644
--- a/lib/tst_test.c
+++ b/lib/tst_test.c
@@ -83,7 +83,7 @@ struct context {
 	tst_atomic_t abort_flag;
 	uint32_t mntpoint_mounted:1;
 	uint32_t ovl_mounted:1;
-	uint32_t tdebug:1;
+	uint32_t tdebug;
 };
 
 struct results {
@@ -216,8 +216,7 @@ void tst_reinit(void)
 	tst_futexes = ipc->futexes;
 	tst_max_futexes = (size - offsetof(struct ipc_region, futexes)) / sizeof(futex_t);
 
-	if (context->tdebug)
-		tst_res(TINFO, "Restored metadata for PID %d", getpid());
+	tst_res(TDEBUG, "Restored metadata for PID %d", getpid());
 }
 
 extern char **environ;
@@ -490,19 +489,20 @@ void tst_res_(const char *file, const int lineno, int ttype,
 	va_list va;
 
 	/*
-	 * Suppress TDEBUG output in these cases:
+	 * Control TDEBUG output in these cases:
 	 * 1. No context available (e.g., called before IPC initialization)
-	 * 2. Called from the library process, unless explicitly enabled
-	 * 3. Debug output is not enabled (context->tdebug == 0)
+	 * 2. Debug output is completely disabled (default: context->tdebug == 0).
+	 * 3. Debug output is only for test process (context->tdebug == 1).
+	 * 4. Debug output is enabled for both test and lib processes (context->tdebug == 2).
 	 */
 	if (ttype == TDEBUG) {
 		if (!context)
 			return;
 
-		if (context->lib_pid == getpid())
+		if (context->tdebug == 0)
 			return;
 
-		if (!context->tdebug)
+		if (context->tdebug == 1 && context->lib_pid == getpid())
 			return;
 	}
 
@@ -657,7 +657,7 @@ static struct option {
 	{"h",  "-h       Prints this help"},
 	{"i:", "-i n     Execute test n times"},
 	{"I:", "-I x     Execute test for n seconds"},
-	{"D",  "-D       Prints debug information"},
+	{"D::", "-D[1,2]  Prints debug information"},
 	{"V",  "-V       Prints LTP version"},
 };
 
@@ -825,8 +825,13 @@ static void parse_opts(int argc, char *argv[])
 			tst_brk(TBROK, "Invalid option");
 		break;
 		case 'D':
-			tst_res(TINFO, "Enabling debug info");
-			context->tdebug = 1;
+			if (optarg)
+				context->tdebug = SAFE_STRTOL(optarg, 1, 2);
+			else
+				context->tdebug = 1;
+
+			if (context->tdebug)
+				tst_res(TINFO, "Enabling debug info (level %d)", context->tdebug);
 		break;
 		case 'h':
 			print_help();
-- 
2.53.0


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